A FIRE chief has told a murder trial that two earlier blazes in the same area had been started deliberately.

Ewan Fraser, 51, a watch commander with Scottish Fire and Rescue, told the High Court in Glasgow he had been in charge when firefighters attended a call to a construction site at Kingspoint, Shandon, near Helensburgh, Argyll and Bute, on July 3 2008.

When they arrived, they found a detached house under construction on fire.

Mr Fraser said: "It was already well alight, we could see the smoke from the fire station. We had multiple calls because it was so big."

He said he later established that the most likely cause was deliberate, with several seats of fire. He added there was a "total destruction" of the property.

He also told the court of a second fire he attended in William Street, Helensburgh, which the court has heard is the home of the McGinley family, on January 6 2011.

Mr Fraser said it appeared an accelerant, possibly petrol, had been used to set alight some paper or card, causing a "small explosion" which was contained to the porch area and did not penetrate the inside door of the house.

He said the blaze was all but extinguished when the fire service arrived.

Scott Snowden, 37, denies, while acting with others, wilful fireraising at the Kingspoint development and along with Robert Jennings, 50, another of wilful fireraising at the house in William Street.

Snowden and Jennings also deny murdering three members of a family by pouring petrol or something similar through their letter box and setting fire to it.

Thomas Sharkey Jnr, 21, and his eight-year-old sister Bridget died in the blaze at their home in Scott Court, Helensburgh, in the early hours of Sunday July 24 2011.

Their father, 55-year-old Thomas Sharkey Snr, died of his injuries in hospital six days later.

Between them, Snowden and Jennings face 22 charges, all of which they deny.

Both men have lodged special defences of incrimination and alibi, with Snowden claiming he was in Mexico when the fire at the Sharkey home was allegedly started while Jennings claims he was at home in Helensburgh.